紫外光激发白光LED用单基质白光荧光粉的制备与性能研究

发布时间：2018-05-19 12:40

本文选题：白光LED + 荧光粉　；参考：《南昌航空大学》2015年硕士论文

【摘要】：白光发光二极管(LED)由于其发光效率高、使用寿命长、环保和安全的优良特性得到了广泛的关注。LED芯片组合荧光粉实现白光是白光LED的主要实现方式,随着紫外LED芯片的出现,基于紫外光激发的白光LED得到了很大的发展空间,由于人眼对紫外光不敏感,得到的白光LED仅由荧光粉发出的颜色决定。为实现高效、稳定的白光LED,荧光粉在其中起着十分重要的作用。所以合成性能优良的适用于紫外LED的荧光粉是决定白光LED技术发展的重要因素之一。本文通过稀土离子掺杂不同含氧酸化合物,得到了适用于紫外光激发单基质白光荧光粉,同时也合成了适用于紫外光激发的蓝色荧光粉,并对其发光性质做了详细探讨。具体的相关实验及结果如下:1.采用溶胶-凝胶法合成了Dy3+和Tm3+激活的GdNbO4单基质白光荧光粉和蓝色荧光粉。研究发现,在紫外光激发下,GdNbO4:Dy3+能够表现为白光发射,其中,GdNbO4:0.02Dy3+荧光粉的CIE坐标为(0.3214,0.3427)。其阴极射线发光(CL)性质与光致发光(PL)性质相似,均呈白光发射。紫外光激发下,GdNbO4:0.02Tm3+呈蓝光发射,发射谱线由Tm3+的1D2-3F4(457 nm)、1D2-3H6(361 nm)跃迁组成。在低压电子束的轰击下,其CL光谱以1D2-3F4(457 nm)为主的蓝光发射,与商用FED蓝粉(Y2SiO5:Ce3+,日亚化学工业株式会社,NP-1047)相比,GdNbO4:Tm3+表现出更好的色纯度和发光强度。2.通过溶胶-凝胶法制备了Eu3+、Tb3+和Dy3+激活的YNbO4荧光粉,得到了色纯度较好的白光发射。研究表明,Eu3+、Tb3+和Dy3+单掺杂YNbO4时,其发射谱线由YNbO4基质宽带蓝光发射和稀土离子(Eu3+、Tb3+、Dy3+)的特征线状发射组成。研究表明在基质和稀土离子之间存在能量传递,并且能量传递效率因离子而异。Eu3+、Tb3+、Dy3+最大能量传递分别为83.7%,91.5%和46.0%。当Eu3+,Tb3+共激活YNbO4基质时,在紫外光激发下,YNbO4:Eu3+,Tb3+的发光颜色由分别来自YNbO4,Eu3+,Tb3+的蓝,红和绿光组成,通过调整Eu3+、Tb3+的掺杂浓度和相对含量(比例)其发光颜色可以从蓝光、蓝绿光、绿光、紫光、红光、白光灯进行调控。在259 nm的紫外光激发下,其中YNbO4:0.015Eu3+,0.02Tb3+荧光粉所发出的白光CIE坐标为(x=0.3275,y=0.3382),与CIE理想的白光(x=0.333,y=0.333)相接近。与Eu3+,Tb3+情况相似,当Eu3+,Dy3+共激活YNbO4基质时,在紫外光激发下,通过调节稀土离子的掺杂浓度可以得到色纯度较好的白光发射荧光粉。通过调整Dy3+、Eu3+的掺杂浓度和相对含量(比例)其发光颜色可以从蓝光、蓝白光、紫光、红光、白光灯进行调控。其中YNbO4:0.02Dy3+,0.04Eu3+同样表现出白光发射,对应的CIE坐标为x=0.3445,y=0.2592。在低压电子束激发下,YNbO4:Dy3+,Eu3+的CL发光性质与PL相类似,并且CL强度随激发电压和灯丝电流强度的增加而增强。3.通过溶胶-凝胶方法制备了(LiGd)0.5TiO3:Dy3+荧光粉,研究发现Dy3+的蓝光区发射(487 nm,4F9/2-6H15/2)较黄光区发射(580 nm,4F9/2-6H13/2)具有更大的发射强度,使得Dy3+单掺在基质(LiGd)0.5TiO3难以呈白光发射。Dy3+的最佳掺杂浓度为4%摩尔分数,通过共掺Eu3+和调节其浓度,在(LiGd)0.5TiO3:Dy3+,Eu3+中实现了近紫外光激发下的单基质白色发射。如(LiGd)0.5TiO3:0.04Dy3+,0.10Eu3+中,在391 nm的近紫外光激发下呈白光发射,其发光颜色对应的CIE坐标为x=0.3691,y=0.3352。进一步研究表明,在(LiGd)0.5TiO3:Dy3+,Eu3+中Dy3+能向Eu3+传递能量,当Eu3+掺杂浓度为30%摩尔分数时,其能量传递效率达到42.0%。4.通过溶胶-凝胶制备了Eu2+,Eu3+和B3+共掺杂的SrAl4O7荧光粉。研究表明,Eu3+在SrAl4O7中有两种不同格位有两种不同格位,即具有反演对称中心和不具有反演对称中心位置。Eu3+在SrAl4O7中的发射位置在B3+掺杂前后有着明显的变化。高温还原可将部分Eu3+还原成Eu2+,且通过改变B3+的掺杂量可以改变Eu2+的发射峰的位置和相对强度。在紫外光激发下,SrAl4O7:0.25B3+,Eu2+,Eu3+具有Eu2+的410和474 nm的宽带发射峰和Eu3+的596和617 nm特征线状发射。优化掺杂浓度和还原条件,能够得到近紫外光激发下的二、三价铕的同时发射的单基质白光荧光粉,如SrAl4O7:0.25B3+,0.03Eu2+/3+荧光粉在383 nm激发下呈白光发射,其对应的CIE坐标为x=0.3251,y=0.2823。将Tb3+引入到SrAl4O7:B3+,Eu2+,Eu3+荧光粉体系中,其白光的色纯度进一步提高。
[Abstract]:White light emitting diode (LED) has been widely concerned because of its high luminous efficiency, long service life, environmental protection and safety. The main realization mode of white light LED is realized by.LED chip combined fluorescent powder. With the appearance of UV LED chip, the white light LED based on ultraviolet light has been greatly developed, due to human eyes. It is not sensitive to ultraviolet light. The obtained white light LED is determined only by the color of phosphor. In order to achieve efficient and stable white light LED, phosphor plays a very important role in it. So the synthesis of fine phosphor suitable for ultraviolet LED is one of the important factors to determine the development of white LED technology. Different oxygen containing compounds have been obtained for ultraviolet light excitation single matrix white light phosphor, and the blue phosphor suitable for UV excitation is also synthesized. The luminescent properties of the phosphor are also discussed in detail. The specific experiments and results are as follows: 1. the single matrix white phosphor activated by Dy3+ and Tm3+ is synthesized by the sol-gel method. It is found that GdNbO4:Dy3+ can show white light emission under UV excitation, in which the CIE coordinates of GdNbO4:0.02Dy3+ phosphors are (0.3214,0.3427). The properties of the cathode ray luminescence (CL) are similar to the properties of photoluminescence (PL), all of which are white light emission. Under ultraviolet light, the GdNbO4:0.02Tm3+ is blue emitting and emitting. The spectral lines are composed of 1D2-3F4 (457 nm) and 1D2-3H6 (361 nm) transitions of Tm3+. Under the bombardment of the low pressure electron beam, the CL spectrum is blue light emitting with 1D2-3F4 (457 nm), which shows better color purity and luminous intensity compared with commercial FED blue powder (Y2SiO5:Ce3+, Japan Asia Chemical Industry Corporation, NP-1047). The Eu3+, Tb3+ and Dy3+ activated YNbO4 phosphors were prepared, and the white light emission with better color purity was obtained. The study showed that when Eu3+, Tb3+ and Dy3+ doped YNbO4, the emission lines were composed of the characteristic linear emission of the YNbO4 matrix broad band blue light emission and the rare earth ions (Eu3+, Tb3+, Dy3+). The study showed that there was a energy transfer between the matrix and the rare earth ions. When the maximum energy transfer of.Eu3+, Tb3+, and Dy3+ is 83.7%, 91.5% and 46.0%., respectively, when Eu3+, Tb3+ activates the YNbO4 matrix, the luminescent colors of YNbO4:Eu3+ and Tb3+ are composed of YNbO4, Eu3+, Tb3+ blue, red and green light excited by ultraviolet light. Quantity (proportion) its luminescence color can be regulated from blue, blue, green, green, purple, red, white light. Under 259 nm ultraviolet light, the white light CIE coordinates of YNbO4:0.015Eu3+ and 0.02Tb3+ phosphors are (x=0.3275, y=0.3382), close to the ideal white light (x=0.333, y=0.333) of CIE, similar to Eu3+, Tb3+, when Eu3+, With the CO activation of YNbO4 matrix, the white light emitting phosphor with better color purity can be obtained by adjusting the doping concentration of rare earth ions under UV excitation. By adjusting the Dy3+, the doping concentration and relative content of Eu3+ can be regulated by blue light, blue white light, purple light, red light and white light lamp. Among them, YNbO4:0.02Dy3+, 0.04 Eu3+ also shows a white light emission, the corresponding CIE coordinates are x=0.3445. Under the excitation of the low pressure electron beam, the CL luminescence properties of YNbO4:Dy3+ and Eu3+ are similar to that of PL, and the CL intensity increases with the increase of the excitation voltage and the filament current intensity, and the.3. is prepared by the sol gel method. The blue light region emission (487 nm, 4F9/2-6H15/2) has a greater emission intensity than the Yellow Zone emission (580 nm, 4F9/2-6H13/2), which makes Dy3+ doped in the matrix (LiGd) 0.5TiO3 with the best doping concentration of 4% mole fraction of the white light emitting.Dy3+. By CO doping Eu3+ and adjusting its concentration, the near ultraviolet excitation is realized in (LiGd) 0.5TiO3:Dy3+. The single matrix white emission below, such as (LiGd) 0.5TiO3:0.04Dy3+, 0.10Eu3+, is emitted in white light under 391 nm near ultraviolet light, and the CIE coordinates of the luminescence color correspond to x=0.3691. Y=0.3352. further studies show that in (LiGd) 0.5TiO3:Dy3+, Eu3+ Dy3+ can transfer energy to Eu3+, when the concentration is 30% mole fraction. The transfer efficiency is 42.0%.4. through the sol-gel preparation of Eu2+, Eu3+ and B3+ Co doped SrAl4O7 phosphors. The study shows that Eu3+ has two different lattice positions in SrAl4O7 and there are two different types of lattice, that is, the launching position of the inverse symmetric center and the non symmetric center position.Eu3+ in SrAl4O7 is obvious before and after B3+ doping. High temperature reduction can restore part of Eu3+ into Eu2+, and change the position and relative strength of the emission peak of Eu2+ by changing the doping amount of B3+. Under UV excitation, SrAl4O7:0.25B3+, Eu2+, Eu3+ have 410 and 474 nm wideband emission peaks of Eu2+ and 596 and 617 nm characteristic linear emission of Eu3+. Optimize doping concentration and reduction conditions. The single matrix white light phosphor emitted at the same time of two, three valence europium excited by near ultraviolet light, such as SrAl4O7:0.25B3+, 0.03Eu2+/3+ phosphor is emitted in white light under the excitation of 383 nm, and its corresponding CIE coordinates are x=0.3251. Y=0.2823. introduces Tb3+ into SrAl4O7:B3+, Eu2+, Eu3+ phosphor system, and its white light color purity is further raised. High.
【学位授予单位】：南昌航空大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN312.8

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